How Long Can I Leave A Cycled Filter Without Fish?

[Katch]

Ah - maths not my strong point but I understand.

So basically I should have no problems once the filter is mature leaving it for a couple of weeks (it'll still be running just no fish)

The tank is only ever lightly stocked - 6 celestials max or a pair of rams.

 

[OldMan47]

If you are going to leave a filter with no fish for 2 weeks, I would feed it a bit of nitrogen daily in the form of some ammonia. I use a sample of ammonia that would not be enough for typical cycling situations but is plenty to keep my bacterial colony healthy and thriving. I will add enough to expect to see a 2 ppm ammonia level right after the dose. I don't even bother to measure the ammonia levels until I am ready to add fish back into the tank. When that day arrives, I measure the ammonia and nitrates in the tank. If nitrates have built too far, I do a huge water change. I have yet to measure any ammonia more than a few hours after the ammonia addition.

 

[waterdrop]

If you are going to leave a filter with no fish for 2 weeks, I would feed it a bit of nitrogen daily in the form of some ammonia. I use a sample of ammonia that would not be enough for typical cycling situations but is plenty to keep my bacterial colony healthy and thriving. I will add enough to expect to see a 2 ppm ammonia level right after the dose. I don't even bother to measure the ammonia levels until I am ready to add fish back into the tank. When that day arrives, I measure the ammonia and nitrates in the tank. If nitrates have built too far, I do a huge water change. I have yet to measure any ammonia more than a few hours after the ammonia addition.

I would like to second this description. I have done -exactly- this for months on end, at times, on my Q-tank. I found it to be very easy (a simple dropper or syringe squirt to that tank at the same time I'm feeding another nearby tank (in fact, I even think of it as just feeding the bacteria, same as the fish.)) I know the dose will be in the 2ppm range but am not particularly careful about the exact amount and don't test the tank except at the end as OM describes.

WD (In my grocery store I can pick up cat food, TetraMin flakes and the correct ammonia all on the same aisle, so they are taking care of helping me feed the household critters along with the humans. )

 

[roadmaster]

I just feed the empty tank (except for snails),a pinch of food once every other day or so.